The present invention relates to food processors in general, and more particularly to improvements in food processors of the type which can be used as blenders, mixers and/or for analogous purposes, e.g., to whip cream, mayonnaise, egg whites and similar foodstuffs. Still more particularly, the invention relates to improvements in food processors of the type wherein a rotary tool is permanently or removably installed in the interior of a bowl to stir and otherwise process the introduced edible material or materials.
It is already known to provide the housing of a food processor with a base which supports a bowl. The bowl can be fixedly attached to the base and its bottom wall is traversed by a spindle or shaft which extends into the interior of the bowl and constitutes the output element of the means for rotating one or more tools. The shaft is provided with suitable coupling elements which can be placed into mesh with complementary coupling elements on any one of a number of various tools so as to drive the selected tool and to thereby enable the machine to perform a slicing, dicing, grating, kneading and/or other operation upon the substance or substances which are admitted into the bowl.
It is also known to construct a food processor in such a way that a bowl or an otherwise configurated receptable can be placed onto the output element of the motor. Such types of food processors are preferred when the bowl invariably contains one and the same type of tool which is coupled to the motor as soon as the bowl is properly installed on a suitable base. Each of a series of discrete bowls can contain a different tool, e.g., one for kneading of dough, one for slicing vegetables or the like, one for chopping meat, one for dicing certain types of foodstuffs, and so forth.
In many instances, a tool which is used in a food processor comprises a centrally located torque receiving hub and one or more blade-like portions which extend outwardly from the hub and serve to treat the material or materials in the bowl. As a rule, each such tool will have not less than two blade-like portions which are then disposed diametrically opposite each other, or three or more blade-like portions which are equidistant from one another, as considered in the circumferential direction of the hub. The blades can be disposed at different levels from the bottom of the bowl, and one or more blades can be provided with protuberances in the form of beads, studs or the like to effect a more pronounced agitation and/or other type of processing of the material or materials in the bowl. Such types of tools can be used for comminuting, stirring and similar purposes.
A drawback of presently known food processors and their presently known tools is that they are not ideally or even reasonably suited for the treatment and processing of certain types of foodstuffs, such as mayonnaise, milk cream and egg whites. It has been found that conventional food processors cannot properly whip cream, egg whites or the like even if the bowl contains a relatively large quantity of such material. The results are even less satisfactory if the user wishes to whip a relatively small quantity of cream or the like.
Attempts to overcome such drawbacks of known food processors involve the utilization of complex, bulky, sensitive and expensive step-down transmissions or other types of (normally electrical) controls which are designed to drive the shaft for the tool in the bowl at a fraction of the normal speed. This greatly increases the initial and maintenance cost of the machine but still fails to ensure satisfactory results. In fact, the results of the processing of cream, mayonnaise, egg whites and the like are often totally unsatisfactory so that the processed material must be discarded.